This protocol (CCM 0404) is part of an overall program to study acute cellular rejection, immunotolerance and cardiac allograft vasculopathy in a rat cardiac transplant model. The rodent model of heterotopic cardiac transplantation is a well established model in the field of solid organ transplantation. The purpose of this protocol is to make provisions to train personnel in the rat cardiac transplant surgical procedure. The anticipated outcome is to master the technical skills prior to the initiation of an animal study, thereby minimizing unnecessary animal suffering and loss due to research procedures. The protocol also allows for the harvesting of organs after euthanizing the animal for the purposes of: histopathological review; training individuals in the sample processing techniques; and providing means for experienced laboratory personnel to develop improved sample processing techniques. There were 40 animals used during the current ACUC reporting period, with a total of 390 used and 3 investigators trained since the protocol was approved.